Refrigeration



A. D. SIEDLE REFRIGERATION June 4, 1946.

Filed July 15, 1942 INVENTOR m d m w n mi ATTORNEY Patented June 4, 1946 imi'i'ao STATES PATENT OFFICE zsolisss' I REFRIGERATION Arnold D. Siedle, Cleveland Heights, Ohio, assign.

or to The Hoover Company, No

rth Canton,

Ohio, a corporation of Ohio Application July 15, 1942, Serial No. 450,975

This application relates to the art of refrigeration and more particularly to a three-fluid absorption refrigerating system of the type in which certain mediums in the system are circulated =byapower operated element.

In three-fluid absorption refrigerating apparatuses of the three-fluid type utilizinga power operated fluid circulator, it has been found that an appreciable time lapse occurs between energization of the system in response to demand for refrigeration and production of refrigerant vapor in the boiler. This time lapse is accentuated if present invention to provide a refrigerating sys-.

tem of the above-identified character characterized by the provision of a-power-operated element for circulating the absorption solution and inert gas coupled with means to prevent circulation of the solution after energization of the circulator in response to a demand for refrigeration until a condition of the system indicating the evolution of refrigerant vapor in the generaim has removed the blocking means from control of solution circulation.

It is a further object of the present invention to provide a system of the above-identified character particularly characterized by the provision of mean for flowing solution through the absorber during the warming up period to remove 15 Claims. (01. 82-5) Referring now to the drawing in detail, and first to Figures 1 and 2v thereof, there is illustrated a three-fluid absorption refrigerating apparatus comprising a generator B, an analyzer D, an air-cooled rectifier R, a tubular air-cooled condenser C, an evaporating element E, a gas.

heat exchanger G, a. tubular air-cooled absorber A. a liquidheat exchanger L, a solution reservoir :8 and a circulating fan or pump F which is 10 driven by an electrical motor M. 'I'hese'elements are suitably interconnected by various conduits to be described more fully hereinafter to form a plurality of fluid circuits constituting a complete refrigerating system.

The refrigerating system will be charged with a refrigerant such as ammonia, an absorbent, such as water, and an inert pressure equalizing medium which in the case of the illustrated form of the invention is preferably a dense she like nitrogen.

A gas burner structure, H is provided for applying heat-to the boiler B. Gas is supplied to the burner H through conduit I which is under the control of a solenoid valve 2. A pilot flame '25 ,by-passt is provided around the valve 2 to maintain a small ignition flame on the burner H.

Electrical energy is supplied totlie apparatus from the line wires 4 and I. The'line wire 4 connects directly to the solenoid valve '2 and the line wire 5 directly to the circulating fan drive motor M. The solenoid valve 2 is connected to a control mechanism 1 by a line 8 and the motor M is connected to the control I by a line 8. The control I i arranged to be,re-- 1 vapor from the inert gas produced .by evaporation sponsive to evaporator temperature, as illustrated,

of refrigerant trapped in the evaporator at the end of a previous operative cycle but without allowing the withdrawal of solution from the generator during this period which would tend to lengthenthe warming up period of the apparatus.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawing, in which-'- 4 Figure 1 is a diagrammatic representation of an absorption refrigerating apparatus embodying the present invention.

Figure 2 is a detail sectional view on an emlarged scale of a portion of the apparatus of Figure 1.

Figure 3 is a fragmentary diagrammatic representation of a modified form of the invention,

though it may also be responsive to air tempercapillary tube II with a suitable bellows and 40 switch mechanism of known type housed within the chamber I. A"preferred form of the control mechanism 1 is illustrated and described in U. 8. Letters Patent No. 2,228,343, dated January 14,1941.

Thus, in response to a demand for refrigeration the circuit is closed by the mechanism I between the lines 8 and 9 and the solenoid valve is energized to openposition "to allow full flow of'sas to the burner Hand the motor M is placed 549 in operation.

The application of heat to the generator B 7 causes evolution of refrigerant vapor from the strong solution therein contained. The vapor so produced passes upwardly through the analyzer 5 D in contact with strong solution returning from the absorber in a manner to be described herein-' 3 after. The resulting vapors-are conducted from the upper portion of the analyzer D to the upper portion of the condenser C by a conduit which includes the rectifier R.-

The lean solution formed in the boiler by the evolution of refrigerant vapor is conveyed therefrom to the solution reservoir S by means of the conduit IE, liquid heat exchanger L, and finned looped pre-cooling conduit H. A gas lift pump conduit I8 is connected between the lower portion of the reservoir S and the lower end of the suction conduit I9 of the circulating fan F. The conduit I9 opens into the upper portion of the absorber A. The upper or gas space of the reservoir S is vented by conduit to the suction conduit IQ of the circulating fan F. Pumping gas is.

supplied to the conduit l8 below the liquid level normally prevailing therein through a conduit 2| which receives gas in a manner to be described hereinafter.

The lean solution which discharges into conduit I9 from gas lift pump conduit [8 flows downwardly through the tubular absorber A in contact with and in counterflow relationship with inert ga containing refrigerant vapor. The solution absorbs refrigerant vapor the resulting heat of absorption is rejected to cooling air flowing in contact with heat rejecting fins provided on the exterior walls of the absorber conduit. The rich solution formed in the absorber flows to the bottom portion thereof from which it is conveyed by conduit 22, liquid heat exchanger L, and conduit 23 to the upper portion of the analyzer D from which it flows downwardly into the boiler B. thus completing the solution circuit. 7

The lean inert gas formed in the absorber'flows upwardly through the conduit l9 into the circufrom the inert gas and 4 low that which will form a complete gas seal in that conduit. Non-volatile matter which i discharged in the evaporator from the condenser is simply propelled upwardly into the conduit of the evaporator and then drains into the gas heat exchanger and flows through the inert gas circuit to the absorber where it returns to the solution circuit.

The enriched inert gas and non-volatile mate- .rial which pass through the evaporator exits from the section 3| of the evaporator through conduit 34 to the inner or rich gas pass of the gas heat exchanger G from which it is then conveyed by the conduit 35 to the bottom portion of the absorber. In th lower portion of the absorber the non-volatile material joins with the rich solution that is thus returned to the solution circuit and the inert gas than flows upwardly through the absorber in' contact with the solution in a manner heretofore described.

A small amount of inert gas under pressure for the gas lift pump 18 is removed from the gas discharge conduit 26 'of the circulating fan! by a conduit 38 which discharges into an hermetically sealed casing 39 surrounding a portion of conduit IS; The gas supply connection 2| to the conduit 18 also opens into th housing 38 (see Figure 2).

Referring now to Figure 2 it is apparent that the conduits 2| and 38 open into the interior of the hermetically sealed casing. The casing 38 houses a snap-acting valve mechanism for controlling the communication between the interior of casing 39 and conduit 88, as will now be described. A suitable supporting bracket 40 is selating fan or pump F wherein it is placed under pressure. The gas under pressure'is then conveyed to the lower portion of way of conduit 26, the outer path of the gas heat the evaporatorE by exchangerG and the evaporator gas supply conduit 21.

The refrigerant vapor which is supplied to the condenser C through conduit I5 is condensed therein by being in heat exchange relationship with atmospheric air and the resulting condensate gravitates to the bottom of the condenser from which point it is conveyed to the bottom portion of the evaporator E adjacent it junction with conduit 21 by way of conduit 28 which includes a U-shaped liquid seal Iorming portion.

The condenser side 01. conduit 28 is-vented by conduit 29 to the rich gas side of the gas heat exchanger. I

The condensate supplied through conduit 28 to the lower portion or the evaporator E meets the inert gas flowing through the conduit 2'1.w The 7 gas is traveling with sufllcient velocity and pressure to distribute the liquid refrigerant throughout the looped conduit portion 30 of the evaporator E and to discharge some of the condensate into the enlarged finned air cooling portion 3| 0! the evaporator E. As the liquid is thus being distributed or propelled through the evaporator by the inert gas, theliquid is also evaporating into the inert gas to produce a refrigeratingeflect.

. The upper portion or the lowermost section-30 of the evaporator E is provided with an overflow conduit 32, which is connected to the rich solution return conduit 22 of the absorber. The purpose of the conduit 32 is not to purge th evaporator of non-condensible materials but to limit the liquid level which can be maintained in the bottom or low'est conduit or the evaporator to a value hecured to a wall of casing 39 adjacent the conduit l5 and serves to support a bi-metallic tl'iermo-' 88 within casing 38 and to Prevent flow of gas into-the casing 39 from conduit 38. 'The supporting plate 40 is provided with a stop lug 41 against which the actuated arm l5v of the snap-acting mechanism will abut when the thermostat has actuated the snap-acting mechanism to remove the sealing disc 48 fromcontact with the open end of conduit 38.

In the operation of this form or the invention ademand for refrigeration will be evidenced by an increase in temperature or the evaporator which will act upon the control mechanism I through the bulb Ill and capillary tube ll, causing closure of thecircuit which will energize the solenoid valve 2 and motorM thus conditionin the system for operation. Immediately-the motor M is energized inert gas will flow through the inert gas circuit including the evaporator, gas heat exchanger and absorber and will produce an initial refrigerating effect in the evaporator E by evaporating refrigerant which collected in the lower portion of the evaporator E up to the level of its point otconnectlon with conduit 32 after completion of a previous operative cycle of the machine. The energlzatlon or the burner H for full flame operation will at the same time apply heat to the boile B and its contents. However, when the apparatu is initially energized for operation the contents of the boiler B will be cool and a period of time 'short period of time.

be hereinafter noted.

mostat 4| to flex to the position illustrated in Figure 2 which will place the disc 46 in contact with the open end .of the conduit 38, thus blocking flow of inert gas through conduit 38, chambeer and conduit 2| to the solution circulating gas lift pump it. As a consequence of this, there will be no solution circulation when the apparatus i initially energized.

Due to thelack of solution circulation when the apparatus is initially energized the liquid in the boiler B and lower portion of the analyzer D will be in a static condition and will therefore quickly heat up to the boiling point and evolution of refrigerant vapor wil1 occur within a As refrigerant vapor is evolved and passes upwardly through conduit l5 enroute to the rectifier R and condenser C the temperature of that conduit will be raised which will heat the thermostat ll sufficiently to cause the same to flex to the right, as viewed in Figure 2, which will actuate the snap-acting mechanism 44 to remove the disc 46 from contact with the conduit 38. When this occurs inert ga will flowthrough conduit 38,-chamber 39 and conduit 2| into gas lift pump l8 and will then begin elevating absorbing solution into the absorber as described previously. As soon as absorption be in a cool condition which will cause the theraccuses the conduit 6| into a valve casing 62 which is mounted on the upper portion of the boiler B. The valve casing 62 is provided interioriy thereof at its left hand end with a. dam 64 arranged to catch the liquid flowing into casing 62 through conduit 6|. The liquid isremoved from the area defined by the left hand-end of casing 62 and dam 64 to the solution reservoir 8' by way of the conduit 63, the liquid heat exchanger L' and the finned looped pre-cooling conduit H. The conduit 68 extends upwardly into the chamber 82 to approximately the liquid level maintained in the analyzer, so that the liquid will flow through conduit 6| at a rate proportionate to the rate at whichfresh liquid is supplied from the absorber to the analyzer D through con solution-begins to pass through conduit I 8 from reservoir S solution will begin to flow from the boiler into thi reservoir and the norms circu- I lation of absorption solution through its circuit will begin. v

This initial delay between energization of the apparatus by the control mechanism and circulation of absorption solution is carried with respect to the production of-refrigeration by the refrigerant which has collected in the lower portion of the evaporator E at the termination of a previous operative cycle. This delay period also allows the boiler to heat up and eflects a considerable saving in energy as partially warm solution is not immediately withdrawn from the boiler, cooled in the absorber and returned thereto.- It is to be noted that the control of the solution circulation'is made directly-responsive cident of evolution of refrigerant vapor from the boiler so thatl solution circulation does not begin until the boiler is in a condition to render circulation of solution necessary and desirable for effective operation of the systeml Referring now to Figures 3 and 4 there is 11- lustrated a modified form of the invention which is identical with the form of the invention illustrated and described above in connection .with Figures 1 and 2 except in certain particulars to Such portions of the apparatus of Figures 1 and; are identical with ap paratu previously illustrated and described in connection with Figures 1' and 2 and they are therefore given the samereference characters distinguished by the addition ofaprime. In this form of-the invention inert gas for operating the circulating pump, I8 is conveyed to a condition of the system produced as an induit 23'.

Interiorly of the chamber 62 there is mounted a bracket 65 which supports a oi-metallic thermostatic element 66 adjacent the upper wall of the boiler and in position to be influenced by the temperature thereof. The outer end of bi-metal 66 carries a link 61 which is connected to an actuating arm 68 of a known type of;snap-acting mechanism indicated at 69- The actuated arm 10 of the snap-acting mechanism 69 carries on its outer" end a valve plate or disc H in position to contactthe open upper end of conduit SI and thus prevent solution flow therethrough. A suitable stop 12 is provided to limit the movement of the actuated arm 10 of the snap-acting mechanism whenthe thermostat 6t actuates the same in a direction to remove the plate I I from contact with the upper end of conduit 68. The chamber 62 is vented by means of a vent conduit I3 to the upper vapor containing space of the analyzer D. The operation "of thi form ofthe invention is as follows: When the apparatus is energized in response to a demand for refrigeration, the boiler will be at a low temperature as a consequence of which the thermostat 66 will have flexed to urge the plate ll into contact withthe open end of conduit 63 and solution flow will be impossible.

The heater for the boiler. B and the circulating fan motor will, however, be energized and .the contents of the boiler will be heated while the inert gas circulates. The circulation of theinert gas .wilievaporate residual refrigerant trapped in the lower portion of the evaporator below the level of its point of connection to conduit 82' which will produce a refrigerating effect to carry the apparatus until the boiler goes into full operation and supplies fresh refrigerant. Also due to the fact that the gas is circulating and gas. is beingsupplied to the conduit 60 from conduit 28' solution will'be removed fromthe reservoir 8" and elevated into the absorber which will serve to absorb refrigerant vapor from the inert gas to sustain the carry over refrigerating effect. Some of this solution will find its way through conduit 23 into the boiler and will raise the level therein" slightly. It is for this reason that the dam l4 extends to a height above the normal solution level in the boiler-analyzer system. However, since no solution is being withdrawn from the boiler B the same will heat up fairly rapidly and there will be no loss of heat due to removal of directly from the gas discharge conduit 28' of the circulating fan F to-thepump I8 by a con duit l0. There are no means in connectionwith warm solution and cooling of the same-in the ab.-

sorber, such as is characteristic of prior systems.

In this formof the invention the lean solution formed in the'boiler B by the evolution of refrigerant vapor is removed therefromthrough By the structures disclosed as exemplifications ofvthe present invention means are provided by which the heater for the boiler and the fluid circulating elements of the system are simultaneously energized which will cause heating of the contentsof the boiler and circulation of inert gas,

but additional means are provided which prevent circulation of solution until the same is allowed by mechanism which is responsive to a condition' produced as an incident to evolution of refrigerant vapor from the generator. By this means the boiler is heated rapidly as no heat is lost due to liquid being withdrawn therefrom, cooled in the absorber and then returned to the boiler. During the interim period a carry-over refrigerating effect is produced by liquid refrigerant which remains in the evaporator after the termination of a previous operative cycle and also in part by liquid which discharges from the condenser into the evaporator after termination, of an operative cycle of the system.

While the invention has been illustrated and described in detail it is not to be limited thereto.

but various changes may be made in the construction, design and arrangement of parts without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. Absorption refrigerating apparatus comprising a boiler; an evaporator, a liquefier and an absorber connected to provide for circulation of a plurality of fluids, a fluid circulating device, means for heating said boiler, refrigeration demand responsive means for energizing said circulating device and said heater in response to a demand for refrigeration, means for preventing circulation of fluid through said boiler, and means responsive to a condition produced as an incident to operation of said boiler for rendering said circulation preventing means inoperative.

2. Absorption refrigerating apparatus comprisinglan inert gas circuit including an evaporator and anabsorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquefied refrigerant to said evaporator, means for heating said generator,

means for circulating inert gas and solution through said inert gas and solution circuit respectively, control means for controlling said heating and circulating means, means arranged to prevent circulation of solution through said solution circuit, and means responsive to the thermal condition of a part of said apparatus for rendering said flow preventing means inoperative to prevent solution circulation.

3. Absorption refrigerating apparatus including a generator, a condenser, an evaporator and an absorber connected to form a plurality of fluid.

circuits, means for heating said generator, fluid circulating means, means normally tending to prevent circulation of fluid in one of said circuits by said fluid circulating means, control means arranged to render said heating means and said fluid circulating means operative in response to demand for refrigeration, and means for rendering said fluid circulating preventing. means inoperative to prevmt fluid circulation.

,, 4, Absorption refrigerating apparatuscomprising an'inert gascircuit including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vaporproduced in said generator and for supplying the liquefied refrigerant tosaid evaporator, means for heating said'generator, power operated means in said inert gas circuit for circulating inert gas therethrough, gas lift lating solution therethrough, means for conduct-' in! vumninggas from said inert gas circuit to gas lift-pump means, refrigeration demand.

responsive means for governing the energization of said power operated means and of said heating dent to operation of said generator for operating m ans, means having a first position in it prevents'circulation of said solution and a second position in which it does not affect circulation of said solution, and means responsive to a condition of the apparatus produced as an incisaid last mentioned means from said first position to said second position.

for circulating inert gas therethrough gas lift pump means in said solution air cult for circulating solution therethrough, means for conducting pumping gas from said inert gas circuit to said gas lift pump means, refrigeration demand responsive means for governing the energization of said power operated means and of said heat- 7 ing means, valve means in said pumping gas conducting means for allowing or preventing gas flow to said gas lift pump, and means responsive to the evolution of refrigerant vapor in said generator for operating said valve means to allow flow of pumping gas to said gas lift pump means.

6. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquefied refrigerant to said evaporator, means for heating said generator, power operated means in said inert gas circuit for circulating inert gas therethrough, gas lift' pump means in-said solution circuit for circulating solution therethrough, means for conducting pumping gas from said inert gas circuit to said gas lift pump means, refrigeration demand responsive means for governing the energization of said power operated means and of said heating means, valve means in said solution circuit for allowing or preventing flow of solution through said solution circuit, and means responsive to the evolution of refrigerant vapor in said generator for operating said valve means'to allow circulation of solution. ,x

7. Absorption refrigerating apparatus comprising an inert gas circuit/including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquefied refrigerant to said evaporator, means-for heating said generator,

power operated means insaid'inert gas circuit for circulating inert gas therethrough, gas lift pump means in said solution circuit for circupump means in said solution circuit for circulating solution therethrough, means for conducting pumping gas from said inert gas circuit to said gas lift pump means,-refrigeration demand responsive means for governing the energization of said power operated means and of said heating means,"areservoir in 'said solution circuit connected to the inlet of said gas lift pump means, valve means insaid solution circuit for allowing or preventing flow of solution through said solution circuit,- and means responsive to the evolution of refrigerant vapor in said generator for operating said valve means to allow circulation of solution, whereby solution is circulated through said absorber from said reservoir while said generator is being heated. r

8. Absorption refrigerating apparatus comprising an absorber, a generator, a condenser, an

evaporator, means for conveying solution from said absorber to said generator, a solution reservoir, means for conveying solution from said generator to said reservoir, gas lift pump means for conveying solution from said reservoir to said absorber, means connecting said evaporator and said absorber to form a circuit for inert gas, means for conveying refrigerant vapor from said generator. to said condenser and for conveying refrigerant liquid from said condenser to said evaporator, inert gas circulating means in said inert gas circuit, means for supplying pumping gas from said inert gas circuit to said gas'lift pump means, said evaporator being constructed and arranged to retain refrigerant liquid therein between ,operative cycles of the apparatus, heating means for said generator, control means for simultaneously rendering said heating means and said inert gas circulating means operative or inoperative in response to refrigeration demand,

and means for. preventing circulation of solution through said generator until said generator has been heated to evolve refrigerant vapor.

. vapor conveying means is not warmed by reirig- 9. Absorption refrigerating apparatus co'mprising an absorber, a generator, a condenser, an

- evaporator, means for conveying solution from said absorber to said generator, a solution reservoir, means for conveying solution from said generator to said reservoir, gas lift pump means for conveying solution from said reservoir to said absorber, means connecting said evaporator and said absorber to form a circuit for inert gas. means for conveying refrigerant vapor from said generator to said condenser and for conveying refrigerant liquid from said condenser to-said evaporator, inert gas circulating means in'said inert gas circuit, means for supplying pumping gas from said inert'gas circuit to said gas lift pump 11. Absorption refrigerating apparatus com-- prising an absorber, a generator, a condenser, an i evaporator, means for conveying refrigerant'vapor from said generator to said condenser and for conveying refrigerant liquid from said condenser to said absorber, means connecting-said generator and said absorber for circulation of absorption solution including a gas lift circulating pump, means connecting said evaporator and said absorber for circulation of. inert gasincluding a gas circulating pump, means for conducting pumping gas from said inert gas circuit to said gas lift pump, a valve in said last-mentioned means and thermostatic meansresponsive to the temperature of'said refrigerant vapor conveying means for opening said valve when said refrigerant vapor conveying means is warmed by vapor and for closing said valve when said refrigerant erant vapor. i

12. Abs'orption refrigerating apparatus comprising an absorber, a generator, a condenser, an evaporator, 'means for conveying refrigerant va-.- por from said generator toisa id condenser, and for conveying-refrigerant liqui fromsaidcondenser to said absorber, means connecting said generator and said absorber for circulation of absorption solutionincluding a gas lift-circulating pump, means connecting said evaporator and said absorber for circulation of inert gas includin a gas circulating pump, means for conducting,

pumping gas from sa dinert gas circuit tosaid gas lift pump, a valve 11 saidsolution circulating means, and thermostatic means responsive to the means, said evaporator being constructed and arranged to retain refrigerant liquid therein between operative cycles of the apparatus, heating means for said generator, control means forgoverning the operation of said heating'means and evaporator, means for conveying solution from said absorber to said generator, a solution reservoir, means for conveying solution from said generator to said reservoir, gas lift pump means for conveying solution from said reservoir to said absorber, means connecting said evaporator and said absorber to-form a circuit for inert gas, means for conveying refrigerant vapor from said generator to said condenser and for conveying refrigerant liquid from said condenser to said evaporator, inert gas circulating means in said inert sas circuit, means for supplying pumping gas from said inert gas circuit to said gas lift pump ,means, said evaporator being constructed and arranged to retain refrigerant liquid therein between operative cycles of the apparatus, heating means for said generator, control means for si-' said inert gas circulating means; and means for temperature of said evaporator, means for conveying refrigerant va-- por from said generator. to saidcondenser and for conveyingrefrigerant liquid from said condenser to said absorber, means connecting'said generator andsaid absorber for circulation'of.

absorption solution including a circulating pump,

50 means connecting said evaporator and said'absorber for circulation of inert gas, a valve insaid solution circulating means, and thermostatic means responsive to the temperatureoi said senerator for opening said valve when said generator is heated sufliciently to evolve refrigerant vapor.

-14. Absorption. refrigerating apparatus com prising an inert gas circuit including an evaporatorand an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in-said generator and for supplying the liquefied refrigerant. 1 I A to said evaporator, means for heating said gen e'i-ato'r, power operated means in said inert gas circuit for circulating inert gas therethrough, gas

multaneously energizing or tie-energizing said.

heating means and saidinert gas circulating means, and means responsive to a condition O-v duced as anincident of operation of said geg erlift pump means in said solution circuit for circulating solution 'therethrollsh. means for conducting pumping gas from said inert gas circuit to said gas lift pump means, refrigeration demand responsive means for governing the energiza'tion' of said power operated means and .of said heating means-valve means having a-first positionin which it prevents circulation'oi' said solution and a second position in which it'does not aflect circulation of said solution,.and' thermostatic means 7Q positioned to be responsive toa rise in the term erator for opening said valve when said gene ator is heated sufficiently- 11 a perature of a part of the refrigerating apparatus produced as an incidentto operation or said generator for operating said valve means from said first position to said second position.

15. Absorption refrigerating apparatus comprising an absorber, a generator, a condenser, an

evaporator, means for conveying solution from said absorber to said generator, a solution reservoir, means for conveying solution from said generator to said reservoir, gas lift pump means forconveying solution from said reservoir to said absorber, means connecting said evaporator and said absorber to form a circuit for inert gas, means for conveying refrigerant vapor from said generator to said condenser and for conveying refrigerant iiquid from said condenser to said evaporator,

. 12 inert gas circulating means in said inert gas circuit, means for supplying umpin gas rrom said inert gas circuit to said gas liit pump means, said evaporator being constructed and arranged t4 retain refrigerant liquid therein between operative cycles of the apparatus, heating means for said generator, control means for governing the operation of said heating means and said inert gas circulating means, means for preventing circuiation of solution until said generator has been heated to evolve refrigerant vapor, and means responsive to the thermal condition of a part of said apparatus for rendering said flow preventing means inoperative to prevent solution circulation.

. ARNOLD D. BIEDLE. 

